Method and system for detecting passages by vehicle at a virtual gantry controlled by a GNSS system comprising an OBU in every vehicle to be surveyed by the system, said OBU receiving signals from satellites to consistently and frequently estimate positions for the vehicle, the method comprising the steps of: defining a virtual gantry in terms of a number of ordered passage lines across a road; determining intersection points from the intersection between the GNSS trace and the passage line; calculating a value representing probability of a true passage at that passage line; for each vehicle for which intersection points have been determined for at least two different passage lines, calculating a total probability value based on the individually calculated probability values; concluding of a true passage by the vehicle in question only if the total probability value is exceeding a predefined minimum value.
Legal claims defining the scope of protection. Each claim is shown in both the original legal language and a plain English translation.
1. A method for detecting passages by vehicles at a virtual gantry controlled by a global navigation satellite system (GNSS) ( 10 ) comprising an on-board unit (OBU) ( 12 ) in every vehicle to be surveyed by the system, said OBU receiving signals from satellites ( 11 ) to consistently and frequently estimate positions for the vehicles, comprising the steps of: (i) defining a virtual gantry in terms of a number of ordered passage lines (PL) across a road, each passage line being further defined by a centre point (c), a local road width (w) and at least one local tolerance (t) defined as a linear extension beyond the local road width (w), (ii) determining an intersection point (I) for each vehicle for which two in succession estimated positions (P k-l , P k ) are localized at different sides of a passage line (PL), as the point where a straight line between the two positions intersects the passage line (PL) in question, (iii) calculating a numerical value representing probability (cpv) of passage at the passage line, as a function ƒ of the determined intersection point (I) in relation to the local road width (w) and local tolerance (t), (iv) calculating a total probability value (TPV) for each vehicle for which intersection points (I) according to step (ii) have been determined for at least two different passage lines (PL i , PL ii , . . . ) within a defined period of time, in the order defined by step (i), based on the individually calculated, contributory probability values (cpv) calculated in step (iii) at each of the at least two passage lines (PL i , PL ii ), (v) determining that the vehicle has truly passed the virtual gantry if the TPV exceeds a predefined minimum value, wherein the total probability value (TPV) is a value obtained from the equation: T P V RMSE = 1 n ∑ i = 1 n f ( d i ) 2 wherein n is the number of passage lines (PL) at the virtual gantry, d i is the signed distance between the position estimate and a centre point at observation i, and ƒ is a mathematical function for which parameters are derived from road widths (w 1 , . . . , w n ) and tolerances (t 1 , . . . , t n ).
A method for detecting vehicle passages at a virtual gantry using a GNSS system. Each vehicle has an onboard unit (OBU) that constantly estimates its position using satellite signals. The method involves: defining the virtual gantry as a series of ordered passage lines across the road, where each line has a center point, a road width, and tolerances (linear extensions beyond the road width); determining the intersection point of the vehicle's GNSS trace with each passage line; calculating a probability value for each passage line based on the intersection point's location relative to the road width and tolerance; calculating a total probability value (TPV) for vehicles that intersect at least two passage lines within a time period, based on the individual passage line probabilities; and determining a true passage only if the TPV exceeds a minimum threshold. The TPV is calculated using a root mean square equation based on the signed distance between the position estimate and the center point, using a mathematical function with parameters derived from road widths and tolerances.
2. The method of claim 1 , wherein one passage line (PL) corresponds to the actual geographic position of the virtual gantry.
The method for detecting vehicle passages at a virtual gantry using a GNSS system, as described in the previous claim, where one passage line corresponds to the actual geographic location of the virtual gantry. Specifically, a virtual gantry is defined as a series of ordered passage lines across the road, where each line has a center point, a road width, and tolerances. The intersection point of the vehicle's GNSS trace is determined with each passage line, a probability value is calculated for each passage line based on intersection point's location, and a total probability value (TPV) is calculated for vehicles intersecting at least two passage lines. A true passage is determined only if the TPV exceeds a minimum threshold. This claim specifies that at least one of those passage lines coincides with the physical location one would expect to find a gantry.
3. The method of claim 1 , wherein the centre points (c) are individually positioned at each virtual gantry and are determined based on at least one factor chosen from the group consisting of local topography, number of driving lanes in each direction, local road width (w), and occurrence of factors assumed to influence the local accuracy of the GNSS system ( 10 ).
The method for detecting vehicle passages at a virtual gantry using a GNSS system, as described in the first claim, where the center points of each passage line are individually positioned based on factors like local topography, number of driving lanes, road width, and factors influencing GNSS accuracy. Specifically, a virtual gantry is defined as a series of ordered passage lines across the road, where each line has a center point, a road width, and tolerances. The intersection point of the vehicle's GNSS trace is determined with each passage line, a probability value is calculated for each passage line based on intersection point's location, and a total probability value (TPV) is calculated for vehicles intersecting at least two passage lines. A true passage is determined only if the TPV exceeds a minimum threshold. The center points are not necessarily evenly spaced or aligned, but adjusted for local conditions.
4. The method of claim 1 , wherein the local road width (w) at a passage line (PL) is calculated as the sum of the longitudinal extension (w left ) of the passage line (PL) to a first or left lateral side of the centre point (c) and the longitudinal extension (w right ) of the passage line (PL) to the other or right lateral side of the centre point (c).
The method for detecting vehicle passages at a virtual gantry using a GNSS system, as described in the first claim, where the local road width at a passage line is calculated by adding the longitudinal extension of the passage line to the left of the center point and the longitudinal extension of the passage line to the right of the center point. Therefore, the road width can be asymmetrical around the center point. Specifically, a virtual gantry is defined as a series of ordered passage lines across the road, where each line has a center point, a road width, and tolerances. The intersection point of the vehicle's GNSS trace is determined with each passage line, a probability value is calculated for each passage line based on intersection point's location, and a total probability value (TPV) is calculated for vehicles intersecting at least two passage lines. A true passage is determined only if the TPV exceeds a minimum threshold.
5. The method of claim 4 , wherein separate local tolerances (t) are defined for each individual longitudinal extension (t left and t right ) at each passage line (PL) based upon occurrence of local factors assumed to influence the accuracy of the GNSS system ( 10 ).
The method for detecting vehicle passages at a virtual gantry using a GNSS system, as described in the previous claim (where the local road width at a passage line is the sum of longitudinal extensions to the left and right of the center point), further defining separate local tolerances for each individual longitudinal extension (left and right) at each passage line, based on factors influencing GNSS accuracy. Thus, not only can the road width be asymmetrical, but the tolerance beyond the road can also differ on each side. Specifically, the local road width is calculated as the sum of the longitudinal extension of the passage line to the left of the center point and the longitudinal extension of the passage line to the right of the center point.
6. The method of claim 1 , wherein the local tolerance (t) defined for the passage lines (PL) constituting a virtual gantry, is a fixed linear distance.
The method for detecting vehicle passages at a virtual gantry using a GNSS system, as described in the first claim, where the local tolerance defined for the passage lines is a fixed linear distance. This means the tolerance, representing the allowable deviation beyond the road width, is constant for all passage lines. Specifically, a virtual gantry is defined as a series of ordered passage lines across the road, where each line has a center point, a road width, and tolerances. The intersection point of the vehicle's GNSS trace is determined with each passage line, a probability value is calculated for each passage line based on intersection point's location, and a total probability value (TPV) is calculated for vehicles intersecting at least two passage lines. A true passage is determined only if the TPV exceeds a minimum threshold. The tolerance is the same for all passage lines.
7. The method of claim 1 , wherein separate local tolerances (t i , t ii , etc.) are defined for each individual passage line (PL) based upon occurrence of local factors assumed to influence the accuracy of the GNSS system ( 10 ).
The method for detecting vehicle passages at a virtual gantry using a GNSS system, as described in the first claim, where separate local tolerances are defined for each individual passage line, based on factors influencing GNSS accuracy. The tolerance, representing the allowable deviation beyond the road width, varies from passage line to passage line. Specifically, a virtual gantry is defined as a series of ordered passage lines across the road, where each line has a center point, a road width, and tolerances. The intersection point of the vehicle's GNSS trace is determined with each passage line, a probability value is calculated for each passage line based on intersection point's location, and a total probability value (TPV) is calculated for vehicles intersecting at least two passage lines. A true passage is determined only if the TPV exceeds a minimum threshold.
8. The method of claim 1 , wherein the local tolerances (t) defined for the passage lines (PL) constituting the virtual gantry are individually defined based upon the presence of nearby or crossing roads.
The method for detecting vehicle passages at a virtual gantry using a GNSS system, as described in the first claim, where the local tolerances defined for the passage lines are individually defined based upon the presence of nearby or crossing roads. The proximity of other roads affects the uncertainty of the GNSS signal, so the tolerance is adjusted accordingly. Specifically, a virtual gantry is defined as a series of ordered passage lines across the road, where each line has a center point, a road width, and tolerances. The intersection point of the vehicle's GNSS trace is determined with each passage line, a probability value is calculated for each passage line based on intersection point's location, and a total probability value (TPV) is calculated for vehicles intersecting at least two passage lines. A true passage is determined only if the TPV exceeds a minimum threshold.
9. The method of claim 1 , wherein the calculated numerical value representing a contributory probability value (cpv), has a fixed maximum for a position detected within the local road width (w) and has a decreased value for positions detected outside the local road width (w), but within the local tolerance (t) reaching a value of zero at the outer end of the local tolerance (t).
The method for detecting vehicle passages at a virtual gantry using a GNSS system, as described in the first claim, where the calculated numerical value representing the contributory probability value (cpv) has a fixed maximum for a position detected within the local road width and decreases for positions outside the road width but within the local tolerance, reaching zero at the tolerance's outer edge. Thus, the probability decreases the further away the intersection point is from the center of the road. Specifically, a virtual gantry is defined as a series of ordered passage lines across the road, where each line has a center point, a road width, and tolerances. The intersection point of the vehicle's GNSS trace is determined with each passage line, a probability value is calculated for each passage line based on intersection point's location, and a total probability value (TPV) is calculated for vehicles intersecting at least two passage lines. A true passage is determined only if the TPV exceeds a minimum threshold.
10. The method of claim 9 , wherein the reduced contributory probability value (cpv) is a value increasing proportionally from a minimum at the outer end of the local tolerance (t) to a maximum at the road edge.
The method for detecting vehicle passages at a virtual gantry using a GNSS system, as described in the previous claim (where the probability value decreases from the road edge to the outer tolerance), where the reduced contributory probability value (cpv) increases proportionally from a minimum (zero) at the outer edge of the local tolerance to a maximum at the road edge. Specifically, the contributory probability value (cpv) has a fixed maximum for a position detected within the local road width and decreases for positions outside the road width but within the local tolerance, reaching zero at the tolerance's outer edge.
11. The method of claim 1 , wherein the calculation of probability of passage is conducted in a manner calculating a complementary value of the probability of passage, namely a probability NPV of non-passage being defined as NPV=1−TPV.
The method for detecting vehicle passages at a virtual gantry using a GNSS system, as described in the first claim, where the calculation of passage probability is conducted by calculating a complementary value: the probability of non-passage (NPV), defined as NPV = 1 - TPV. This provides an alternative way to evaluate whether a vehicle has passed the gantry; instead of directly calculating the probability of passage (TPV), the probability of non-passage is calculated and then used to infer the passage probability. Specifically, a virtual gantry is defined as a series of ordered passage lines across the road, where each line has a center point, a road width, and tolerances. The intersection point of the vehicle's GNSS trace is determined with each passage line, a probability value is calculated for each passage line based on intersection point's location, and a total probability value (TPV) is calculated for vehicles intersecting at least two passage lines. A true passage is determined only if the TPV exceeds a minimum threshold.
12. The method of claim 1 wherein some or all passage lines (PL) may be defined as compulsory to pass.
The method for detecting vehicle passages at a virtual gantry using a GNSS system, as described in the first claim, where some or all passage lines are defined as compulsory to pass. This means that a valid gantry passage requires intersection with these specific passage lines in the correct order. Specifically, a virtual gantry is defined as a series of ordered passage lines across the road, where each line has a center point, a road width, and tolerances. The intersection point of the vehicle's GNSS trace is determined with each passage line, a probability value is calculated for each passage line based on intersection point's location, and a total probability value (TPV) is calculated for vehicles intersecting at least two passage lines. A true passage is determined only if the TPV exceeds a minimum threshold. Not every passage line is treated equally; some are essential.
13. A system for detecting passages by a vehicle at a virtual gantry controlled by a global navigation satellite system (GNSS) system ( 10 ) comprising an on-board unit (OBU) ( 12 ) in every vehicle to be surveyed by the system, said OBU receiving signals from satellites ( 11 ) to consistently and frequently estimate positions for the vehicle, the system further comprising: software programmed to (i) define a virtual gantry in terms of a number of ordered passage lines (PL) across a road, a local road width (w) and at least one local tolerance (t) defined as a linear extension beyond the local road width (w), and (ii) determine an intersection point (I) as the point where a straight line between the two positions (P i , P ii ) intersects the passage line (PL) in question for each vehicle for which two in succession estimated positions (P i , P ii ) are localized at different sides of a passage line (PL), (iii) calculate a numerical value representing the probability (cpv) of true passage at the passage line (PL), as a function of the determined intersection point (I) in relation to local road width (w) and local tolerance (t), (iv) calculate a total probability value (TPV) based on the individually calculated, contributory probability values (cpv) calculated at each of the at least two passage lines (PL i , PL ii ) for each vehicle for which intersection points (I) have been determined for at least two different passage lines (PL i , PL ii , . . . ) within a defined period of time, in the order mentioned above, and (v) determining that the vehicle has truly passed the virtual gantry if the total probability value (TPV) exceeds a predefined minimum value, wherein the total probability value (TPV) is a value obtained from the equation: TPV RMSE = 1 n ∑ i = 1 n f ( d i ) 2 wherein n is the number of passage lines (PL) at the virtual gantry, d i is the signed distance between the position estimate and a centre point at observation i, and ƒ is a mathematical function for which parameters are derived from road widths (w 1 , . . . , w n ) and tolerances (t 1 , . . . , t n ).
A system for detecting vehicle passages at a virtual gantry controlled by a GNSS system. Each vehicle has an onboard unit (OBU) that constantly estimates its position using satellite signals. The system includes software that: defines a virtual gantry as a series of ordered passage lines across the road, where each line has a center point, road width, and tolerances (linear extensions beyond road width); determines the intersection point of the vehicle's GNSS trace with each passage line; calculates a probability value for each passage line based on the intersection point's location relative to road width and tolerance; calculates a total probability value (TPV) for vehicles that intersect at least two passage lines within a time period, based on individual passage line probabilities; and determines a true passage only if the TPV exceeds a minimum threshold. The TPV is calculated using a root mean square equation based on the signed distance between the position estimate and the center point, using a mathematical function with parameters derived from road widths and tolerances.
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December 4, 2014
May 30, 2017
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